BEIJING, Dec. 22 -- Lung cancer may run through family members, researchers said but without denying tobacco smoke as the main cause of such a disease.

    

Lung cancer appears to run in families, researchers said on Tuesday, though exposure to tobacco smoke is still the dominant cause of the disease even for those who may be genetically predisposed.

Researchers from Landspitali-University Hospital in Reykjavik, Iceland had released a report that genetic link might be a cause to the terrible disease -- lung cancer.

    The strongest family link was found in the relatives of patients who developed the disease at age 60 or younger. The parents of such people had nearly a three and one-half times higher risk of also developing the disease compared to the general population, the report said.

    For brothers and sisters in such cases the risk was more than three times higher and for children slightly less than that.

    The genetic risk of lung cancer may run beyond the immediate family, said the report. Aunts and uncles, cousins, nieces and nephews of lung cancer victims of any age also run a higher risk, though at lower levels than the immediate family.

    The Icelandic researchers said they traced the genetic links by looking at all 2,756 patients diagnosed with lung cancer in the country from 1955 to 2002 and linking them with an extensive genealogical database containing all living Icelanders and most of their ancestors since the settlement of the country.

    "The nationwide genealogy database used in our study provided a means for uncovering the familial component by revealing more connections between patients, missed in most other populations," the study said.

    Lung cancer is the leading cause of cancer deaths among men and women in many Western countries, said the study, published in this week's Journal of the American Medical Association, and smokers comprise about 90 percent of all cases. Enditem

    (Agencies)